Density of air
Dry air

Temperature T (°C)
Speed of sound c (m/s)
Density of air ρ (kg/m3)
Characteristic specific acoustic impedance z0 (Pa·s/m)
35
351.88
1.1455
403.2
30
349.02
1.1644
406.5
25
346.13
1.1839
409.4
20
343.21
1.2041
413.3
15
340.27
1.2250
416.9
10
337.31
1.2466
420.5
5
334.32
1.2690
424.3
0
331.30
1.2922
428.0
−5
328.25
1.3163
432.1
−10
325.18
1.3413
436.1
−15
322.07
1.3673
440.3
−20
318.94
1.3943
444.6
−25
315.77
1.4224
449.1

Question: How's air like at 20 °C?
Answer: At 20 °C, dry air has a density of 1.2041 kg/m³.